Local area ring networks based on the IEEE 802.5 standard have been very successful in providing multiple access interconnections among computers, workstations, terminals and other peripherals using metallic media operating at rates of 1 Megabits/second to 4 Megabits/second (Mb/s). The FDDI standard, which is a fiber optic token-passing ring operating at a rate of 100 Mb/s or 200 Mb/s for dual counter-rotating rings, is widely viewed as the next generation ring. FDDI can operate at distances up to 100 km and serve up to 500 nodes.
There is much recent research to develop Gigibits/second (Gb/s) networks. A typical example of this approach is the AT&T Lucky net which has the goal of using SONET and ATM standards to provide up to 2.4 Gb/s throughput on a fiber media. Network architectures such as employed by LuckyNet build on the B-ISDN standards and technologies presently being developed for long distance telephony. Other approaches include: Hewlett-Packard's HANGMAN which operates at a baud rate of 1.3 Gb/s, having a maximum internode spacing of up to 10 km, and an individual user data rate of up to 800 Mb/s; and the Gigabit Nector Testbed at Carnegie-Mellon University which operates at the SONET OC-48 data rate of 2.488 Gb/s and uses a SONET/ATM interface.
These approaches are designed to be fully compatible with the future SONET/ATM standards which are expected to be adopted for the broadband switched public network, but they have the disadvantage that the electronic integrated circuits required for performing all the SONET and ATM processing at these high data rates are still in the state of development. This development will likely require GaAS IC technology and will be expensive. Additionally, all nodes or stations on such gigabit/sec networks must perform digital processing at the specified throughput data rate, thus limiting the flexibility of such configurations.